1. Field of the Invention
The present invention relates to means for retaining a boot on a gliding board adapted for snowboarding. More particularly, the invention relates to means for retaining a boot that allows for bending or inclination movements of the leg with respect the user's foot.
2. Background and Material Information
In snowboarding, the user operates his board on trajectories that can be substantially straight or curved. In any case, the operation can be precise only if the supports of the board on the snow are controlled by the user.
Experience shows that control of the supports is readily done when the trajectories are relatively straight, but that control is delicate, or even impossible when the trajectories are curved.
Indeed, the user is always led to make movements with the body or limbs to manage his balance at the same time as he operates his board. It has proven very difficult to perfectly coordinate balance management and board operation in curved trajectories, in turns or on a bump.
In fact, the movements made to maintain the balance disturb the control of the supports that is necessary for a precise operation. In particular, when the user bends or inclines the legs to maintain balance, he cannot, at the same time, avoid causing a change, sometime severe, in the inclination of the board with respect to the ground.
This change in the inclination generally has the effect of severely modifying the contact surface of the board on the ground. As a result, the operation is disturbed and the control of the trajectory is random, because the reaction forces of the ground on the board vary in considerable proportions.
This phenomenon is particularly notices when the user needs to keep balance and to press toward the ground with the side of the board located behind him.
The prior art has proposed devices that provide a certain positioning flexibility between each foot and the board.
It is, for example, the case of the document FR 2 650 752 whose object is to enable the user to place himself in the most comfortable and balanced position during the displacements, due to flexible journals arranged between the feet and the board. The device according to the document FR 2 650 752 does not, however, enable the user to manage the variations in the support. Indeed, the flexibility of the journals does not promote a precise guiding, and does not enable the user to properly identify the sensorial information which he receives. Therefore, this devices is not really satisfactory, and mastering the trajectories is difficult, even impossible.
The document DE 89 02 125 proposes a device for retaining a boot on a board which includes a journalled shell on a base along a transverse axis. The journal enables the device to be folded for transportation. A removable elastic means is capable of maintaining the shell with respect to the base in a usage position. The elastic means acts to limit the bending movement of the lower part of the leg toward the foot. It follows that the user can easily take supports with the forefoot.
On the contrary, it is not possible for the user to easily master curved trajectories because of the elasticity of the device. In particular, it is practically impossible to keep a selected curved trajectory in the case where it is necessary to manage both the balance and the support on the ground with the side of the board located behind the user.